import java.util.HashSet;
import java.util.Set;

public class test {
    public static void main(String[] args) {
        Set<String> s = new HashSet<>();
        s.add("hello");
        Set<Set<String>> ss = new HashSet<>();
        ss.add(s);
        System.out.println(ss.contains(s)); // 输出: true

        s.add("Hi");
        s.remove("hi");
        System.out.println(ss.contains(s)); // 输出: false
        System.out.println(ss);
        System.out.println(s);
        s.add("sads");
        s.remove("sads");

        Set<Set<String>> ss2 = new HashSet<>(ss);
        System.out.println("test"+(ss.equals(ss2)));
        System.out.println(ss2.contains(s)); // 输出: true
        System.out.println(s);
        System.out.println(ss);
        System.out.println(ss2);
    }
}